RSA加密解密，分段加密，分段解密，部分汉字乱码详解
package com.tysu.mall.core.util;
/**
* 创建时间:2019/01/10
* 创建人:Administrator
* 描述:
*/
import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
/**
* 1、公钥加密，私钥解密用于信息加密
* 2、私钥加密，公钥解密用于数字签名
*/
public class RsaTool{
//定义加密方式
public static final String KEY_RSA = "RSA";
//定义公钥关键词
public static final String KEY_RSA_PUBLICKEY = "RSAPublicKey";
//定义私钥关键词
public static final String KEY_RSA_PRIVATEKEY = "RSAPrivateKey";
//定义签名算法
private final static String KEY_RSA_SIGNATURE = "MD5withRSA";
/**
* **
* RSA最大加密大小
*/
private final static int MAX_ENCRYPT_BLOCK = 117;
/**
* **
* RSA最大解密大小
*/
private final static int MAX_DECRYPT_BLOCK = 128;
/**
* 生成公私密钥对
*/
public static Map<String, Object> init()
{
Map<String, Object> map = null;
try
{
KeyPairGenerator generator = KeyPairGenerator.getInstance(KEY_RSA);
//设置密钥对的bit数，越大越安全，但速度减慢，一般使用512或1024
generator.initialize(1024);
KeyPair keyPair = generator.generateKeyPair();
// 获取公钥
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
// 获取私钥
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
// 将密钥对封装为Map
map = new HashMap<String, Object>();
map.put(KEY_RSA_PUBLICKEY, publicKey);
map.put(KEY_RSA_PRIVATEKEY, privateKey);
} catch (NoSuchAlgorithmException e)
{
e.printStackTrace();
}
return map;
}
/**
* 获取Base64编码的公钥字符串
*/
public static String getPublicKey(Map<String, Object> map)
{
String str = "";
Key key = (Key) map.get(KEY_RSA_PUBLICKEY);
str = encryptBase64(key.getEncoded());
return str;
}
/**
* 获取Base64编码的私钥字符串
*/
public static String getPrivateKey(Map<String, Object> map)
{
String str = "";
Key key = (Key) map.get(KEY_RSA_PRIVATEKEY);
str = encryptBase64(key.getEncoded());
return str;
}
/**
* BASE64 解码
*
* @param key 需要Base64解码的字符串
* @return 字节数组
*/
public static byte[] decryptBase64(String key)
{
return Base64.getDecoder().decode(key);
}
/**
* BASE64 编码
*
* @param key 需要Base64编码的字节数组
* @return 字符串
*/
public static String encryptBase64(byte[] key)
{
return new String(Base64.getEncoder().encode(key));
}
/**
* 公钥加密
*
* @param encryptingStr
* @param publicKeyStr
* @return
*/
public static String encryptByPublicKey(String encryptingStr, String publicKeyStr)
{
try
{
// 将公钥由字符串转为UTF-8格式的字节数组
byte[] publicKeyBytes = decryptBase64(publicKeyStr);
// 获得公钥
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
// 取得待加密数据
byte[] data = encryptingStr.getBytes("UTF-8");
KeyFactory factory;
factory = KeyFactory.getInstance(KEY_RSA);
PublicKey publicKey = factory.generatePublic(keySpec);
// 对数据加密
Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
// 返回加密后由Base64编码的加密信息
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0)
{
if (inputLen - offSet > MAX_ENCRYPT_BLOCK)
{
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else
{
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return encryptBase64(decryptedData);
} catch (Exception e)
{
e.printStackTrace();
}
return null;
}
/**
* 私钥解密
*
* @param encryptedStr
* @param privateKeyStr
* @return
*/
public static String decryptByPrivateKey(String encryptedStr, String privateKeyStr)
{
try
{
// 对私钥解密
byte[] privateKeyBytes = decryptBase64(privateKeyStr);
// 获得私钥
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
// 获得待解密数据
byte[] data = decryptBase64(encryptedStr);
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
PrivateKey privateKey = factory.generatePrivate(keySpec);
// 对数据解密
Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateKey);
// 返回UTF-8编码的解密信息
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0)
{
if (inputLen - offSet > MAX_DECRYPT_BLOCK)
{
cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
} else
{
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return new String(decryptedData, "UTF-8");
} catch (Exception e)
{
e.printStackTrace();
}
return null;
}
/**
* 私钥加密
*
* @param encryptingStr
* @param privateKeyStr
* @return
*/
public static String encryptByPrivateKey(String encryptingStr, String privateKeyStr)
{
try
{
byte[] privateKeyBytes = decryptBase64(privateKeyStr);
// 获得私钥
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
// 取得待加密数据
byte[] data = encryptingStr.getBytes("UTF-8");
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
PrivateKey privateKey = factory.generatePrivate(keySpec);
// 对数据加密
Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
// 返回加密后由Base64编码的加密信息
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0)
{
if (inputLen - offSet > MAX_ENCRYPT_BLOCK)
{
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else
{
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return encryptBase64(decryptedData);
} catch (Exception e)
{
e.printStackTrace();
}
return null;
}
/**
* 公钥解密
*
* @param encryptedStr
* @param publicKeyStr
* @return
*/
public static String decryptByPublicKey(String encryptedStr, String publicKeyStr)
{
try
{
// 对公钥解密
byte[] publicKeyBytes = decryptBase64(publicKeyStr);
// 取得公钥
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
// 取得待加密数据
byte[] data = decryptBase64(encryptedStr);
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
PublicKey publicKey = factory.generatePublic(keySpec);
// 对数据解密
Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicKey);
// 返回UTF-8编码的解密信息
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0)
{
if (inputLen - offSet > MAX_DECRYPT_BLOCK)
{
cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
} else
{
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return new String(decryptedData, "UTF-8");
} catch (Exception e)
{
e.printStackTrace();
}
return null;
}
/**
* 用私钥对加密数据进行签名
*
* @param encryptedStr
* @param privateKey
* @return
*/
public static String sign(String encryptedStr, String privateKey)
{
String str = "";
try
{
//将私钥加密数据字符串转换为字节数组
byte[] data = encryptedStr.getBytes();
// 解密由base64编码的私钥
byte[] bytes = decryptBase64(privateKey);
// 构造PKCS8EncodedKeySpec对象
PKCS8EncodedKeySpec pkcs = new PKCS8EncodedKeySpec(bytes);
// 指定的加密算法
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
// 取私钥对象
PrivateKey key = factory.generatePrivate(pkcs);
// 用私钥对信息生成数字签名
Signature signature = Signature.getInstance(KEY_RSA_SIGNATURE);
signature.initSign(key);
signature.update(data);
str = encryptBase64(signature.sign());
} catch (Exception e)
{
e.printStackTrace();
}
return str;
}
/**
* 校验数字签名
*
* @param encryptedStr
* @param publicKey
* @param sign
* @return 校验成功返回true，失败返回false
*/
public static boolean verify(String encryptedStr, String publicKey, String sign)
{
boolean flag = false;
try
{
//将私钥加密数据字符串转换为字节数组
byte[] data = encryptedStr.getBytes();
// 解密由base64编码的公钥
byte[] bytes = decryptBase64(publicKey);
// 构造X509EncodedKeySpec对象
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(bytes);
// 指定的加密算法
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
// 取公钥对象
PublicKey key = factory.generatePublic(keySpec);
// 用公钥验证数字签名
Signature signature = Signature.getInstance(KEY_RSA_SIGNATURE);
signature.initVerify(key);
signature.update(data);
flag = signature.verify(decryptBase64(sign));
} catch (Exception e)
{
e.printStackTrace();
}
return flag;
}
}